Semiconductor device and manufacturing method thereof

ABSTRACT

A first semiconductor element is mounted on a base plate, and is in a sealed state by the periphery thereof being covered by an insulation member, and the upper surface thereof being covered by an upper insulation film. An upper wiring layer formed on the upper insulation film, and the lower wiring layer formed below the base plate via lower insulation films are connected by conductors. A second semiconductor element is mounted exposed, being connected to the lower wiring layer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device andmanufacturing method thereof.

2. Description of the Related Art

A multi chip semiconductor device wherein a plurality of semiconductorchips are mounted on the island of the lead frame, each semiconductorchip is bonded with an internal lead by wire, and the mounted pluralityof semiconductor chips are resin molded entirely is disclosed inUnexamined Japanese Patent Application KOKAI Publication No.2002-368184. This semiconductor device occupies a large mounting(occupation) area, because a plurality of semiconductor chips aremounted on one lead frame resulting in a large lead frame. Also themanufacturing cost is high, because wire bonding using a lead frame isadopted.

A semiconductor device having a small mounting area is disclosed inUnexamined Japanese Patent Application KOKAI Publication No.2003-273321. This semiconductor device has a plurality of double-sidedsubstrates on each of which a semiconductor chip or chips are mounted.The substrates are stacked or laminated by, for example, a hot pressing.

A semiconductor device disclosed in Unexamined Japanese PatentApplication KOKAI Publication No. 2001-094046, has two stacked barechips mounted on center of an upper surface of a base plate. Connectingpads provided on periphery area of the upper surface of each bare chipare connected with connecting pads provided on periphery of the uppersurface of the base plate by bonding wires. To enable wire bonding ofthe lower-side bare chip, the size of the upper-side bare chip issmaller than that of the lower-side bare chip so that the periphery ofthe upper surface of the lower bare chip is exposed, and the connectingpads provided on the upper bare chip is at an inner side than theconnecting pads provided on the lower bare chip. Further, because wirebonding of the upper bare chip is carried out after that of the lowerbare chip, at the upper surface of the base plate, the connecting padsfor the lower bare chip are arranged outside of the mounting area thelower bare chip, and the connecting pads for the upper bare chip arearranged at the outer side thereof.

The semiconductor device disclosed in above mentioned UnexaminedJapanese Patent Application KOKAI Publication No. 2003-273321, hasdouble-sided boards on which a semiconductor chip is mounted, bypolymerizing a conductive connection terminal formed on eachdouble-sided board. As for this semiconductor device, because eachcircuit board is thick and expensive, the entire semiconductor device isalso thick and expensive. Also, because each layer is bonded, it is hardto obtain reliability of intensity, in accordance with environmentalchange. The semiconductor device disclosed in Unexamined Japanese PatentApplication KOKAI Publication No. 2001-094946, because the connectingpads for the lower bare chip are arranged at the upper surface of thebase plate, and the connecting pads for the upper bare chip are arrangedat the outer side thereof, when the number of stacked semiconductorchips increase, the area occupied by pads on the base plate becomeslarger. Therefore, the area of the entire semiconductor device becomeslarger. Further, because the length of the wire becomes longer, thevalue of resistance becomes larger, and becomes inadaptable to a highfrequency.

Therefore an object of the present invention is to provide asemiconductor device of which the mounting area is small and areliability of intensity in the connecting units is secured, and amanufacturing method thereof.

SUMMARY OF THE INVENTION

To achieve the above object, a semiconductor device according to a firstaspect of the present invention comprises:

-   -   a first semiconductor element that has a plurality of electrodes        for external connection;    -   an insulation member provided at the periphery of the fist        semiconductor element;    -   an upper layer wiring structure provided at an upper surface        side of the first semiconductor element and the insulation        member;    -   a lower layer wiring structure provided at a lower surface side        of the first semiconductor element and the insulation member;        and    -   a second semiconductor element that is mounted on at least, one        of the upper layer wiring structure and the lower layer wiring        structure.

A manufacturing method of the semiconductor device according to a secondaspect of the present invention comprises:

-   -   forming a first semiconductor element wherein each semiconductor        element comprises a plurality of electrodes for external        connection, by the base plate, the insulation film, and the        upper insulation film, by respectively sealing;    -   forming an upper rerouting on the upper insulation film;    -   forming a lower rerouting layer below the base plate; mounting a        second semiconductor element on at least either the upper        rerouting layer or the lower rerouting layer; and    -   obtaining a plurality of semiconductor devices that comprise at        least one semiconductor element and at least one second        semiconductor element, by cutting the base plate, the insulation        member, and the upper insulation film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a semiconductor device according toa first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a component initially prepared formanufacturing the semiconductor device shown in FIG. 1.

FIG. 3 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 2.

FIG. 4 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 3.

FIG. 5 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 4.

FIG. 6 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 5.

FIG. 7 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 6.

FIG. 8 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 7.

FIG. 9 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 8.

FIG. 10 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 9.

FIG. 11 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 10.

FIG. 12 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 11.

FIG. 13 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 12.

FIG. 14 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 13.

FIG. 15 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 14.

FIG. 16 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 15.

FIG. 17 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 16.

FIG. 18 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 17.

FIG. 19 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 18.

FIG. 20 is a cross-sectional view of a semiconductor device according toa second embodiment of the present invention.

FIG. 21 is a cross-sectional view of the semiconductor device in amanufacturing step, for describing a manufacturing method of thesemiconductor device shown in FIG. 20.

FIG. 22 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 21.

FIG. 23 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 22.

FIG. 24 is a cross-sectional view of the semiconductor device in amanufacturing step succeeding the step of FIG. 23.

FIG. 25 is a cross-sectional view of a semiconductor device according toa third embodiment of the present invention.

FIG. 26 is a cross-sectional view of a semiconductor device according toa fourth embodiment of the present invention.

FIG. 27 is a cross-sectional view of a semiconductor device according toa fifth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT First Embodiment

A semiconductor device according to the first embodiment of the presentinvention will be described with reference to the cross-sectional viewof FIG. 1. This semiconductor device comprises a rectangular shaped baseplate 1. The base pale is made of, for example epoxy base resinpermeated into a glass fabric base. An upper layer wiring 2 made ofcopper foil is formed on the upper surface of the base plate 1, and alower layer wiring 3 made of copper foil is formed on the lower surfaceof the base plate I. The upper layer wiring 2 serves as a ground wiringand has a pattern formed on substantially the whole surface. The lowerlayer wiring 3 serves as a current source (power source) wiring and hasa pattern formed on substantially the whole surface.

A semiconductor element 4 is provided on the upper wiring 2. Morespecifically, the semiconductor element 4 has a rectangular outer shapeand has a size smaller than that of the base plate 1 to a certainextent. The bottom surface of the semiconductor element 4 is attached tothe upper surface of the upper wiring 2 via an adhesive layer 5 made ofa die-bonding substance. The semiconductor element 4 compriseslater-described distributing wiring layers, columnar electrodes, and asealing film, and is generally called a CSP (Chip Size Package). Thesemiconductor element 4 is also called a wafer level CSP (W-CSP) becausea semiconductor element 4 is obtained by dicing a silicon wafer, afterthe distributing wiring layers, columnar electrodes, and a sealing filmare formed on the wafer.

The structure of the semiconductor element 4 will be described in detailbelow.

The semiconductor element 4 comprises a silicon substrate (semiconductorsubstrate) 6. The silicon substrate 6 is attached to the base plate 1via the adhesive layer 5. An integrated circuit (not shown) having apredetermined function (for example, function as a CPU) is formed in theupper surface region of the silicon substrate 6. A plurality ofconnecting pads 7 connected to the integrated circuit and made ofaluminum alloy, etc., are formed on the periphery of the upper surface.An insulation film 8 made of silicon oxide, etc., is formed on the uppersurface of the silicon substrate 6 excluding the center portions of theconnecting pads 7. The center portions of the connecting pads 7 areexposed via openings 9 provided in the insulation film 8.

An overcoat film (insulation film) 10 made of epoxy resin, or polyimideresin, etc., is formed on the insulation film 8. Openings 11 are formedin the areas of the overcoat film 10 that correspond to (overlap with)the openings 9 of the insulation film 8. Base metal layers 12 made ofcopper, etc., are provided on the upper surface of the overcoat film 10.Distributing wiring layers 13 made of copper are provided on the entireupper surface of the base metal layers 12, respectively. The base metallayers 12 and the stacked distributing wiring layers 13 serve asmulti-layered (two-layered) distributing wiring layers (reroutinglayers) as a whole. One end portion of each distributing wiring layers13 including respective base metal layer 12 is connected to therespective connecting pad 7 via both openings 9 and 11.

Columnar electrodes (external connection electrode) 14 made of copperare provided on the upper surfaces of connecting pads of thedistributing wiring layers 13. The height of each columnar electrode 14is 60 to 150 μm. A sealing film (insulation film) 15 made of epoxy resinor polyimide resin, etc., is provided on the upper surface of theovercoat film 10 including the distributing wiring layer 13, such thatthe upper surface of the overcoat film 10 is flush with the uppersurface of the columnar electrode 14.

In this way, the semiconductor element 4, called the W—CSP, comprisesthe silicon substrate 6, connecting pads 7, insulation film 8, theovercoat film 10, distributing wiring layers 13, columnar electrodes 14,and the sealing film 15.

An insulating layer 16 having a rectangular frame like shape is formedon the upper surface of the base plate 1 including the upper layerwiring 2, so as to surround the periphery of the semiconductor element4. The upper surface of the insulating layer 16 is substantially flushwith the upper surface of the semiconductor element 4. The insulationlayer 16 is made of for example, thermosetting resin, or resin includinga reinforcer such as glass fiber or silica filler, etc., diffusedtherein.

A first upper insulation film 17 is provided on the upper surface of thesemiconductor element 4 and the insulation layer 16, such that the uppersurface thereof is flat. The first upper insulation film 17 is made ofso-called build-up material commonly used in, for example, a build-upsubstrate, and for example is made of thermosetting resin such as epoxyresin or BT (Bismaleimide Triadin) resin, etc., including a reinforcersuch as fiber or filler, etc., diffused therein. The fiber may be glassfiber or aramid fiber, etc. The filler may be silica filler or ceramicsfiller, etc.

Openings 18 are formed in the first upper insulation film 17 and on thecenter portions of the columnar electrodes 14, respectively. First upperbase metal layers 19 made of copper, etc., are formed on the uppersurfaces of the first upper insulation films 17. First upperdistributing wiring layers 20 made of copper are provided on the entireupper surfaces of the first upper base metal layers 19, respectively.The first upper base metal layers 19 and the stacked first upperdistributing wiring layers 20 serve as multi-layered (two-layered)distributing wiring layers (rerouting layers) as a whole. One endportion of each first upper base metal layer 19 and the first upperdistributing wiring layer 20 is connected to the upper surface ofrespective columnar electrode 14 via respective opening 18 formed in thefirst upper insulation film 17.

A second upper insulation film 21 made of the same material as the firstupper insulation film 17 is provided on the upper surface of the firstupper distributing wiring layer 20 and the first upper insulation film17. Openings 22 are formed in the areas of the second upper insulationfilm 21 that correspond to at least a part of the connecting pad ofrespective first upper distributing wiring layer 20. Second upper basemetal layer 23 made of copper, etc., are provided on the upper surfacesof the second upper insulation films 21, respectively. Second upperdistributing wiring layers 24 made of copper are provided on the uppersurface of the second upper base metal layers 23, respectively. Thesecond upper base metal layers 23 and the stacked second upperdistributing wiring layers 24 serve as multi-layered (two-layered)distributing wiring layers (rerouting layers). At least a part of endportion of each second upper base metal layer 23 and the second upperdistributing wiring layer 24 is connected to the connecting pad of thefirst upper distributing wiring layer 20 via the opening 22 of thesecond upper insulation film 21.

A top insulation film 25 made of solder resist, etc., is provided on theupper surface of the second upper distributing wiring layer 24 and thesecond upper insulation film 21. An opening 26 is provided in the partof the top insulation film 25 that corresponds to the connecting pad ofthe second upper distributing wiring layer 24. A plurality of solderballs 27 are provided in the interior and upside of the opening 26 beingconnected to the connecting pad of the second upper distributing wiringlayer 24. The plurality of solder balls 27 are arranged in a matrix, ontop of the top insulation film 25.

A lower insulation film 31 made of the same material as the first upperinsulation film 17 is provided on the lower surface of the base plate 1and the lower layer wiring 3. And the lower surface of a lowerinsulation film 31 is flat. First lower base metal layers 32 made ofcopper, etc., are provided on the lower surfaces of the first lowerinsulation films 31, respectively. First lower distributing wiringlayers 33 made of copper are provided on almost entire lower surfaces ofthe first lower base metal layers 32, respectively. The base metallayers 32 and the stacked first distributing wiring layers 33 serve asmulti-layered (two-layered) distributing wiring layers (reroutinglayers) as a whole.

A second lower insulation film 34 made of the same material as the firstupper insulation film 17 is provided on the lower surface of the firstlower distributing wiring layers 33 and the first lower insulation film31. Openings 35 are formed in the areas of a second lower insulationfilm 34 that correspond to the connecting pads of the first lowerdistributing wiring layers 33. Second lower base metal layers 36 made ofcopper, etc., are provided on the lower surfaces of the second lowerinsulation films 34. Second lower distributing wiring layers 37 made ofcopper are provided on the entire lower surfaces of the second lowerbase metal layers 36, respectively. The second lower base metal layers36 and the stacked second lower distributing wiring layers 37 serve asmulti-layered distributing wiring layers as a whole. At least a part ofone end portion of each second lower distributing wiring layers 37including respective second lower base metal layer 36 is connected tothe connecting pad of the respective first lower distributing wiringlayer 33 via the respective opening 35 formed in the second lowerinsulation film 34.

A bottom insulation film 38 made of solder resist, etc., is provided onthe lower surfaces of the second lower distributing wiring layers 37 andthe second lower insulation films 34. Openings 39 are formed in theareas of the bottom insulation film 38 that correspond to the connectingpads of the second lower distributing wiring layers 37. A plurality ofsemiconductor elements 40 are mounted at the lower surface of the bottominsulation film 38 in the state that a plurality of solder balls 41provided on the upper surface of the semiconductor elements 40 areconnected to the connecting pads of the second lower distributing wiringlayers 37 via the openings 39 in the bottom insulation film 38.

Though the detail of the semiconductor element 40 is not shown in thedrawings, the semiconductor element 40 may be a bare chip, a BGA (BallGrid Array), or a CSP, etc. Each of the semiconductor elements 40 has asemiconductor substrate made of silicon, etc. An integrated circuithaving a predetermined function (for example, function as asemiconductor memory) is formed in the upper surface region of eachsemiconductor substrate. A plurality of connecting pads which are madeof aluminum, etc. and connected to the integrated circuit, are formed atthe periphery areas of upper surface of each semiconductor substrate.Solder balls 41 are provided on the connecting pads or externalconnecting electrodes such as columnar electrodes, connected to theconnecting pads.

Penetrating (through) hole 42 are formed so as to penetratepredetermined places of the first upper insulation film 17, theinsulation layer 16, the base plate 1 including the upper layer wiring 2and the lower layer wiring 3, the first lower insulation film 31, thefirst lower distributing wiring layer 33 including the first lower basemetal layer 32 (layers 32 and 33 are provided at a position not shown inFIG. 1), and the second lower insulation film 34. Vertical conductors 43are formed on the inner wall of the penetrating holes 42, respectively.Each vertical conductor 43 comprises a base metal layer 43 a made ofcopper, etc. formed on the inner wall of the hole 42, and a copper layer43 b formed on the base metal layer 43 a.

The second upper distributing wiring layer 24 including the second upperbase metal layer 23, the first upper distributing wiring layer 20including the upper base metal layer 19, the upper wiring 2 or the lowerwiring 3, and the second lower distributing wiring layer 37 includingthe second lower base metal layer 36, are connected by the verticalconductors 43. In FIG. 1, the upper wiring 2 is connected to the leftside vertical conductor 43, and the lower wiring 3 is connected to theright side vertical conductor 43.

To make the electric conductivity of the vertical conductor 43 higher, aconductivity material 44 made of copper paste, silver paste,conductivity resin, etc., is filled in the vertical conductor 43.Instead, insulation resin may be filled in the vertical conductor 43, orthe interior of the vertical conductor 43 may be hollow.

As an example, the columnar electrode 14 for the ground is connected tothe upper layer wiring 2 served as the ground wiring via the first upperdistributing wiring layer 20 and the vertical conductor 43. The columnarelectrode 14 for power source is connected to the lower layer wiring 3served as the power source wiring via the first upper distributingwiring layer 20 and the vertical conductor 43.

The solder ball 41 for the ground of the semiconductor element 40 isconnected to the upper wiring 2 served as the ground wiring, via thesecond lower distributing wiring layer 37 and the vertical conductor 43.The solder ball 41 for power source of the semiconductor element 40 isconnected to the lower wiring 3 served as the power source wiring, viathe second lower distributing wiring layer 37 and the vertical conductor43.

The solder ball 41 for signal of the semiconductor element 40 isconnected to the columnar electrode 14 for signal of the semiconductorelement 4 via the first upper distributing wiring layer 20, the verticalconductor 43, the first lower distributing wiring layer 33, and thesecond lower distributing wiring layer 37. The ground wiring includinglayers 2, 23, 24, 36, and 37 and vertical conductor 43 is connected tothe solder ball 27 for ground. The power source wiring including layers3, 23, 24, 36, and 37 and the vertical conductors 43 is connected to thesolder ball 27 for power source. The signal wiring connected to a signalterminal of the semiconductor element 4 or 40 is connected to the solderball 27 for signal.

As an example, the thickness of the silicon substrate 6 is 0.1 to 0.35mm, the thickness of the columnar electrode 14 is 0.06 to 0.15 mm, thethickness of the semiconductor element 4 is 0.25 to 0.5 mm, the totalthickness of the first upper insulation film 17 to the top insulationfilm 25 is 0.2 to 0.25 mm, the total thickness of the base plate 1 tothe bottom insulation film 38 is 0.25 to 0.3 mm, the thickness of thesemiconductor element 40 is 0.25 to 0.3 mm, and the entire thickness is1.0 to 1.2 mm.

The reason that the base plate 1 is larger than the semiconductorelement 4 to a certain extent in plane, is for obtaining the enougharrangement area where the solder balls 27 are arranged in matrix formlarger than the semiconductor element 4 in accordance with the number ofthe connecting pads 7 on the silicon substrate 6, thereby making thesize and pitch of the connecting pads (interior conductive parts of theopenings 26 in the top insulation film 25) in the second upperdistributing wiring layer 24 larger than the size and pitch of thecolumnar electrodes 14.

The connecting pads in the second upper distributing wiring layer 24arranged in a matrix form (rows and columns) are arranged on not onlythe region corresponding to the semiconductor element 4, but also to theregion that corresponds to the insulation layer 16 provided outside ofthe perimeter side surface of the semiconductor element 4. In otherwords, of the solder balls 27 arranged in a matrix, at the least, thesolder balls 27 at the most outer circumference are arranged outside ofthe semiconductor element 4.

In this semiconductor device, the semiconductor element 4 works as a CPUis provided on above the base plate 1, and a plurality of semiconductorelements 40 works as semiconductor memories are provided below the baseplate 1. In other words, semiconductor elements having differentfunctions are stacked with each other. Therefore, the size or occupationarea of the semiconductor device can be smaller than that of the devicewhere the semiconductor elements are arranged on one plane. Therefore,the size of the device can be small even if the semiconductor devicecomprises semiconductor elements 4, 40 having different functions.Further, according to this embodiment, the number of steps for formingthe semiconductor device can be reduced compared with a case where thesewirings 2 and 3 are formed by the build-up process, because the upperlayer wiring 2 and lower layer wiring 3 made of copper foils areprovided on the upper and lower surface of the base plate 1.

Next, an example of a manufacturing method of this semiconductor devicewill be described.

First, an example of the manufacturing method of the semiconductorelement 4 will be described.

A silicon substrate (semiconductor substrate) 6 in a wafer state, shownin FIG. 2, is prepared. Integrated circuits having a predeterminedfunction are formed in each element region of the silicon substrate 6.Connecting pads 7 electrically connected to respective integratedcircuits are formed on the upper surface region of the semiconductorsubstrate 6. The connecting pads 7 may be made of aluminum, etc. On thesubstrate 6 and the connecting pads 7, an insulation film 8 made ofsilicon oxide, etc., and the overcoat film 10 made of epoxy resin, orpolyimide resin, etc., are formed. The center portions of the connectingpads 7 are exposed by the openings 9, 11 formed in the insulation film 8and the overcoat film 10.

Next, as shown in FIG. 3, a base metal layer 12 is formed on the entireupper surface of the overcoat film 10 and the center portions of theconnecting pads 7 exposed via both openings 9 and 11. The base metallayer 12 may be a copper layer formed by electroless deposition(plating) or sputtering. Further, the base metal layer 12 may have amulti-layered structure comprises, for example, a thin film layer oftitanium, etc., formed on the substrate 6 by sputtering and a copperlayer formed on the thin film by spattering.

A plating resist film 51 is formed on the resultant structure. Then, theplating resist film 51 is patterned by, for example, PEP (Photo EtchingProcess), so that openings 52 are formed in the areas corresponding tothe regions on which the distributing wiring layers 13 are to be formed.Distributing wiring layers 13 are formed on the upper surface of thebase metal layer 12 in the openings 52 of the plating resist film 51 byperforming electrolytic plating of cupper using the base metal layer 12as a plating current path (electrodes). Then, the plating resist film 51is removed.

Next, as shown in FIG. 4, a plating resist film 53 is formed on theresultant structure, namely, on the on the upper surface of the basemetal layer 12 and the distributing wiring layers 13. Then, the platingresist film 53 is patterned by, for example, the PEP so as to fromopenings 54 at areas on which the columnar electrodes 14 are to beformed later. Then, by electrolytic plating of copper using the basemetal layer 12 and the distributing wiring layers 13 as a platingcurrent path, columnar copper layers are grown in the openings 54 of theplating resist film 53 and on the connecting pads areas of thedistributing wiring layers 13. When the columnar electrodes 14 having adesired thickness are formed, the plating is stopped. The plating resistfilm 53 is removed. Then the unnecessary parts of the base metal layer12 are removed by etching by using the distributing wiring layers 13 asthe etching masks, thereby as shown in FIG. 5, the base metal layer 12is left only below the distributing wiring layers 13.

As shown in FIG. 6 by a screen printing, a spin coating, or a diecoating, etc., a sealing film 15 made of epoxy resin or polyimide resin,etc., is formed on the resultant structure, namely, on entire uppersurface of the columnar electrode 14, the distributing wiring layer 13,and the overcoat film 10, such that the thickness thereof is thickerthan the height of the columnar electrodes 14. In this state, the uppersurfaces of the columnar electrodes 14 are covered with the sealing film15 as shown in FIG. 6.

The upper surfaces of the sealing films 15 and the columnar electrodes14 is polished, by for example, the CMP (Chemical Mechanical Polishing)to expose the upper surface of the columnar electrode 14 and flatten theupper surface of the sealing film 15 and the upper surfaces of theexposed columnar electrodes 14, as shown in FIG. 7. The columnarelectrodes 14 formed by the plating have different heights, thepolishing makes the columnar electrodes 14 to have an equal height.

As shown in FIG. 8, an adhesive layer 5 is adhered to the entire lowersurface of the silicon substrate 6. The adhesive layer 5 is made of diebond material such as epoxy resin, and polyimide resin, etc., and isfixed to the silicon substrate 6 by hot pressing in a state ofhalf-hardened. Next the adhesive layer 5 fixed to the silicon substrate6 is attached to a dicing tape (not shown).

The wafer is diced as shown in FIG. 9, thereby to obtain a plurality ofsemiconductor elements 4 that comprise the adhesive layer 5 on the lowersurface of the silicon substrate 6. By separating the adhesive layer 5from the dicing tape, the semiconductor element 4 shown in FIG. 1 isobtained.

Because the semiconductor element 4 obtained in this way comprises theadhesive layer 5 on the lower surface of the silicon substrate 6, it isunnecessary to provide an adhesive layers at the lower surface of thesilicon substrate 6 of each of the semiconductor element 4. Theoperation for separating the adhesive layer from the dicing tape is easycompared with the operation for respectively providing an adhesive layerto the lower surface of the silicon substrate 6 of each thesemiconductor element 4.

Next, an example of a manufacturing method of the semiconductor devicewith the semiconductor element 4 obtained in this way will be described.

First, as shown in FIG. 10, a plane rectangular base plate 1 with a sizewhich a plurality of base plates 1 can be obtained is prepared. Theplane shape of the base plate 1 is not limited to a rectangular. Copperfoils are laminated to the upper and lower surface of the base plate 1.The upper layer wiring 2 and the lower layer wiring 3 are formed bypatterning the copper foils with photolithography. A number of pairs ofupper layer wiring 2 and the lower wiring layer are formed on the baseplate 1 in a matrix form.

Then, the adhesive layers 5 adhered to each lower surface of the siliconsubstrates 6 of the semiconductor element 4 are adhered to predeterminedplaces on the upper surface of the base plate 1. Here, the adhesivelayers 5 are fully hardened by hot pressing. A predetermined number ofthe semiconductor elements 4 are arranged on the base plate 1 in amatrix form.

A first insulation material 16 a is mounted on the upper surface of thebase plate 1. More specifically, the first insulation material 16 a ismounted on the upper surface of the base plate 1, and between thesemiconductor elements 4 and at the outer side of the semiconductorelements 4 by a screen printing or a spin coating, etc.

A sheet-form second insulation material 17 a is arranged on the uppersurface of the semiconductor elements 4 and first insulation material 16a. A sheet-form third insulation material 31 a is arranged on the lowersurface of the base plate 1.

The first insulation material 16 a is made of thermosetting resin, orthermosetting resin that includes a reinforcer such as glass fiber orsilica filler, diffused therein. It is preferable that the sheet-formsecond and third insulation materials 17 a and 31 a are made of build upmaterial. However it is not limited to the build up material. As thisbuild up material, there is material that is half-hardened thermosettingresin such as epoxy resin or BT resin, etc into which silica filler ismixed. As the second and third insulation materials 17 a and 31 a,prepreg of a sheet-form by impregnating thermosetting resin such asepoxy resin, etc., into a glass fabric base, and half-hardening thethermosetting resin, or material made of only thermosetting resin whichdoes not include filler mixed therein, may be used.

The first to third insulation materials 16 a, 17 a, and 31 a are hotpressed by using a pair of hot pressing plates 55, 56, shown in FIG. 11.Thereby, an insulation layer 16 is formed on the upper surface of thebase plate 1 in between the semiconductor elements 4 and semiconductorelements 4 arranged at the most outer circumference in the matrix, afirst upper insulation film 17 is formed on the upper surface of thesemiconductor element 4 and the insulation layer 16, and a first lowerinsulation film 31 is formed on the lower surface of the base plate 1.

The upper surface of the first upper insulation film 17 becomes flat,because the upper surface of the first upper insulation film 17 is helddown by the lower surface of the hot pressing plate 55 at the upperside. Also the lower surface of the first lower insulation film 31becomes flat, because the lower surface of the first lower insulationfilm 31 is held down by the upper surface of the hot pressing plate 56at the lower side. Therefore the polishing process flattening the uppersurface of the first upper insulation film 17 and the lower surface ofthe first lower insulation film 31 is unnecessary. By this, even if thesize of the base plate 1 is relatively large, for example approximately500×500 mm, the upper surface of the first insulation film 17 and thelower surface of the first lower insulation film 31 can be flattened atthe same time the first insulation film 17 and the insulation film 31are formed on the plurality of semiconductor elements 4 arranged on thebase plate 1.

As shown in FIG. 12, openings 18 are formed in the parts of the firstinsulation film 17 corresponding to the upper surface center portions ofthe columnar electrodes 14 by irradiating a laser beam. An opening isnot formed in the first insulation film 31. If need, epoxy smear, etc.,generated in the openings 18, etc., of the first upper insulation film17 is removed by desmearing processing.

Next, as shown in FIG. 13, a first upper base metal layer 19 is formedon the entire upper surface of the first upper insulation film 17 andthe upper surfaces of the columnar electrodes 14 exposed via theopenings 18, by electroless copper plating, etc. Also, a first upperbase metal layer 32 are formed on the entire lower surface of the firstlower insulation film 31, by electroless copper plating, etc.

Then an upper plating resist film 61 is formed on the upper base metallayer 19 and a lower plating resist film 62 is formed on the lower basemetal layer 32. The upper plating resist film 61 is patterned so as toform the openings 63, and a lower plating resist film 62 is patterned soas to form the openings 64. The openings 63 are formed in the regions onwhich the first upper distributing wiring layers 20 are to be formed.The openings 64 are formed in the regions on which the lowerdistributing wiring layers 33 are to be formed.

The first upper distributing wiring layers 20 are formed on the uppersurface of the first upper base metal layer 19 in the openings 63 of theupper plating resist film 61, and the first lower distributing wiringlayers 33 are formed on the lower surface of the first lower base metallayer 32 in the openings 64 of the lower plating resist film 62, byelectrolytic plating of copper using the base metal layers 19, 32 as theplating current path.

The plating resist films 61, 62 are removed, then the unnecessaryportions of the first upper base metal layer 19 and the first lower basemetal layer 32 are removed by etching with using the first upperdistributing wiring layer 20 and the first lower distributing wiringlayer 33 as the mask. By this process, as shown in FIG. 14, the firstupper base metal layer 19 is left only below the first upperdistributing wiring layers 20, and the first lower base metal layer 32is left only below the first lower distributing wiring layers 33.

As shown in FIG. 15, a second upper insulation film 21 is formed on theupper surface of the first upper distributing wiring layers 20 and thefirst upper insulation film 17 by a screen printing, a spin coating, ora die coating, etc., and a second lower insulation film 34 is formed onthe lower surfaces of the first lower insulation film 31 and the firstlower distributing wiring layers 33. The same material as the firstupper insulation film 17 may be used for the second upper insulationfilm 21 and the second lower insulation film 34. However, they may beformed of a different material from the first upper insulation film 17described above.

As shown in FIG. 16, openings 22 are formed in the areas of the secondupper insulation film 21 so as to expose at least parts of theconnecting pad regions of the first upper distributing wiring layers 20by irradiating a laser beam. Openings 35 are formed in the areas of thesecond lower insulation film 34 so as to expose at least parts of theconnecting regions of the first lower distributing wiring layer 33.

Then, by using a mechanical drill, by irradiating a CO₂ laser beam, orby punching, etc., penetrating (through) holes 42 are formed inpredetermined places of the second upper insulation film 21, the firstupper distributing wiring layer 20 and the first upper base metal layer19, the first upper insulation film 17, the insulation layer 16, thebase plate 1, the upper layer wiring 2, the lower layer wiring 3, thefirst lower insulation film 31, the first lower distributing wiringlayer 33 and the first lower base metal layer 32 provided at positionsthat are not shown in FIG. 16, and the second lower insulation film 34.Then, in accordance with necessity, epoxy smear, etc., generated in theopenings 22, 35, and the penetrating hole 42 etc., is removed bydesmearing processing.

As shown in FIG. 17, a metal layer is formed on the entire upper surfaceof the second insulation film 21, the connecting pads of the first upperdistributing wiring layers 20 exposed via the openings 22, the entirelower surface of the second lower insulation films 34, the connectingpads of the first lower distributing wiring layers 33 exposed via theopenings 35, and the inner wall surfaces of the penetrating holes 42, byelectrolytic plating of copper, etc. The formed metal layer constitutesthe second upper base metal layer 23, the second lower base metal layer36, and the base metal layer 43 a.

Then an upper plating resist film 65 is formed on the second uper basemetal layer 23 and a lower plating resist film 66 is formed on thesecond lower base metal layer 36.

Then, the upper plating resist film 65 is patterned to form openings 67in the upper plating resist film 65 and in areas corresponding to thepenetrating holes 42 and the regions in which the second upperdistributing wiring layers 24 are to be formed as shown in FIG. 17.Further, the lower plating resist film 66 is patterned to form openings68 in the lower plating resist film 65 and in areas corresponding to thepenetrating holes 42 and the regions in which the second lowerdistributing wiring layers 37 are to be formed in FIG. 17.

By electrolytic plating of copper using the base metal layers 23, 36,and 43 a, as a plating current path, a second upper distributing wiringlayer 24 is formed on the upper surface of the second upper base metallayer 23 in the opening 67 of the upper plating resist film 65, and asecond lower distributing wiring layer 37 is formed on the lower surfaceof the second lower base metal layer 36 in the opening 68 of the lowerplating resist film 66, and further, a copper layer 43 b is formed onthe surface of the base metal layer 43 a in the penetrating hole 42.

Next, the plating resist films 65, 66 are removed. Then the unnecessaryparts of the second upper base metal layer 23 and the second lower basemetal layer 36 are removed by etching with using the second upperdistributing wiring layer 24 and the second lower distributing wiringlayer 37 as masks. Thereby, as shown in FIG. 18, the second upper basemetal layer 23 is left only below the second upper distributing wiringlayer 24, and the second lower base metal layer 26 is left only below ofthe second lower distributing wiring layer 37.

In this state, as one example, the columnar electrodes 14 for ground ofthe semiconductor element 4 is connected to the upper distributingwiring layer 2 served as the ground wiring via the first upperdistributing wiring layer 20 and the vertical conductors 43. Thecolumnar electrode 14 for power source of the semiconductor element 4 isconnected to the lower distributing wiring layer 3 served as the powersource wiring via the first upper distributing wiring layer 20 and thevertical conductors 43.

As shown in FIG. 19, conductive material 44 made of copper paste, silverpaste, or conductive resin, etc., is filled in the vertical conductors43 by a screen printing, etc. Next, in accordance with need, extraconductive material 44 protruding from the penetrating hole 42 isremoved by a buffing, etc.

Next, a top insulation film 25 made of solder resist, etc., is formed onthe upper surface of the second upper distributing wiring layer 20 andthe second upper insulation film 21 by the screen printing or the spincoating etc. In this case, openings 26 are formed in the parts of thetop insulation film 25 that corresponds to the connecting pads of thesecond upper distributing wiring layers 24.

By the screen printing or the spin coating, etc., the bottom insulationfilm 38 made of solder resist, etc., is formed on the lower surface ofthe second lower distributing wiring layer 37 and the second lowerinsulation film 34. In this case, openings 39 are formed in the parts ofthe bottom insulation film 38 that correspond to the connecting pads ofthe second lower distributing wiring layers 37.

The solder balls 41 are connected to the connecting pads of the secondlower distributing wiring layers 37 via the openings 39 of the bottominsulation film 38.

Then the semiconductor elements 40 are mounted on the lower surface ofthe bottom insulation film 38. Next, the solder balls 27 are connectedto the connecting pads of the second upper distributing wiring layers 24via the openings 26.

The solder balls 41 for ground of the semiconductor element 40 isconnected to the upper layer wiring 2 served as the ground wiring viathe second lower distributing wiring layer 37 and the verticalconductors 43. The solder ball 41 for power source of the semiconductorelement 40 is connected to the lower layer wiring 3 served as the powersource wiring via the second lower distributing wiring layer 37 and thevertical conductors 43. The solder balls 41 for signal of thesemiconductor elements 40 are connected to the columnar electrodes 14for signal of the semiconductor element 4 via the first upperdistributing wiring layer 20, the vertical conductors 43, the firstlower distributing wiring layer 33, and the second lower distributingwiring layer 37.

Then a plurality of semiconductor devices shown in FIG. 1 are obtainedby cutting (dicing) the top insulation film 25, the second upperinsulation layer film 21, the first upper insulation film 17, theinsulation layer 16, the base plate 1, the first lower insulation film31, the second lower insulation film 34, and the bottom insulation film38 between the respectively adjacent semiconductor elements 4.

According to the above mentioned manufacturing method, the manufacturingprocess can be simplified, because forming of the upper layer wiring 2,the lower layer wiring 3, the first and second upper distributing wiringlayers 20 and 24, the first and second lower distributing wiring layers33 and 37, the vertical conductors 43, and the solder ball 27 arecarried out, to the plurality of semiconductor elements 4 placed on thebase plate 1, and a plurality of semiconductor devices are obtaineddicing the resultant structure thereafter, Because each insulation filmand distributing wiring layer is formed so that they are stackedadhesively, compared with the conventional semiconductor device, it ispossible to thin the entire thickness of the semiconductor device.

Also the manufacturing process can be simplified, because the pluralityof semiconductor elements 4 can be transferred together with the baseplate 1 in the steps after the step shown in FIG. 1. Further areliability with respect to the intensity of the device can be assuredcompared with the method of thermo-compression, because connectionsbetween the electrode and the distributing wiring layer, and between thedistributing wiring layers are formed by plating.

The columnar electrodes 14 have a height of approximately 0.1 mm. So,even in a case where stress occurs by the difference of thermalexpansion of the silicon substrate 6 and the circuit substrate (notshown) due to change in environment, concentration of stress can beavoided by fluctuation of the columner electrodes in the horizontaldirection.

In the above embodiment, the upper layer wiring 2 serves as the groundwinding and is formed at substantially the whole surface, and the lowerlayer wiring 3 serves as the power source wiring and is formed atsubstantially the whole surface. However, this invention is not limitedto this, and the upper layer wiring 2 may serve as the power sourcewinding and the lower layer wiring 3 may serve as the ground wiring.

Also, the upper layer wiring 2 and/or the lower wiring 3 may serve asshield layers and/or general circuit patterns. Further, the upper layerwiring 2 and/or lower layer wiring 3 may be formed on only partial areasand/or have arbitral pattern.

In the above embodiment, the CPU is formed in the silicon substrate 6 ofthe semiconductor element 4. However, the circuits formed in thesubstrate 6 are arbitral. For example, an SOI (Silicon On Insulator)including a thin film transistors formed on an insulation film may beformed in the silicon substrate 6. In this case, micro strip lines maybe formed by the upper wiring 2 serving as the ground winding and formedat substantially the whole surface and the adhesive layer 5 made ofconductive material.

In the above embodiment, both the upper distributing wiring layer andthe lower distributing wiring layer have two layered structure. However,it is not limited to this. Each of the upper distributing wiring layerand the lower distributing wiring layer may be formed by one layer orequal to or more than three layers. Also, the numbers of layer(s) of theupper distributing wiring layer and the lower distributing wiring layermay be different from each other.

Further, a chip-part or chip-parts made of a capacitor or a resistor,etc., may be mounted on the bottom insulation film 38.

Further, in the above embodiment, the semiconductor element 4 is mountedon the base plate 1 in a face-up mounting state. However, it may bemounted in a face-down state by providing a pad unit to the base plate1.

The semiconductor elements 40 are mounted on the second lowerdistributing wiring layer 37 which is the bottom layer at the lowersurface side of the base plate 1. However, the semiconductor elements 40may be mounted on the second upper distributing wiring layer 24 which isthe top layer, or may be mounted on both surfaces of the second lowerdistributing wiring layer 37 and the second upper distributing wiringlayer 24. In a case where the semiconductor elements 40 are mounted atthe lower surface side of the base plate 1, it is possible that lowerdistributing wiring layer may be directly provided on the lower surfaceof the base plate 1 and the semiconductor element(s) 40 is mounted onthe lower distributing wiring layer.

In the embodiment, the semiconductor elements 40 are mounted in aface-down state. However, the face-up mounting of the semiconductorelements are possible. An example thereof will be described as thesecond embodiment.

Second Embodiment

In the second embodiment shown in FIG. 20, a first semiconductor element71 and a second semiconductor element 77 mounted on the second lowerdistributing wiring layer 37 are face-up mounted, differed from thefirst embodiment shown in FIG. 1. Below the difference between thesecond embodiment and the first embodiment will be described mainly. Thesame reference numbers are used for the parts that have the samestructure as the first embodiment, and the overlapping description willbe omitted.

In the same way as the first embodiment, a second lower distributingwiring layer 37 that includes a second lower base metal layer 36 isformed on the lower surface of a second lower insulation film 34.However, the pattern is in accordance with the bonding positions of thelater described first external semiconductor element 71 and a secondexternal semiconductor element 77.

A bottom insulation film 38 made of solder resist, etc., is provided onthe lower surface of the second lower insulation film 34 and the secondlower distributing wiring layer 37. An opening 39 is provided in thepart of the bottom insulation film 38 that corresponds to the connectingpad of the second lower distributing wiring layer 37. A first and secondsurface layers 70 a and 70 b made of gold are provided on the lowersurfaces of the connecting pads of the second lower distributing wiringlayers 37 in the openings 39. The first surface layers 70 a are arrangedon the peripheries of the mounting regions of the later described firstexternal semiconductor element 71, and the second surface layers 70 bare arranged on the peripheries thereof.

The lower surface of the first external semiconductor element 71 isadhered to the lower surface center portion of the bottom insulationfilm 38 via an adhesive layer 72 made of die bond material. The firstexternal semiconductor element 71 is ordinarily called a bare chip. Andthe first external semiconductor element 71 has a silicon substrate 73(semiconductor substrate), an integrated circuit provided on the centerregion of the main surface (lower surface in FIG. 20) of a siliconsubstrate 73, a plurality of connecting pads 74 made of aluminum metal,etc., connected to the integrated circuit, and an insulation film 75made of oxide silicon, etc covering the connecting pads 74 excluding thecenter portion thereof. The connecting pads 74 of the first externalsemiconductor element 74 are connected to the first surface layer 70 avia a first bonding wire 76.

The lower surface of a second exterior semiconductor element 77 isadhered to the lower surface center portion of the first externalsemiconductor element 71 via an adhesive layer 78 made of die bondmaterial. In the same way as the first external semiconductor element71, the second exterior semiconductor element 77 is a bare chip. Thesize thereof is smaller than the size of the first exteriorsemiconductor element 71 only to a certain extent. Because the basicstructure of the second semiconductor element 77 is the same as thefirst exterior semiconductor element 71, the detailed descriptionthereof will be omitted. Connecting pads 79 of the second externalsemiconductor element 77 are connected to the second surface layers 70 bvia a second bonding wire 80 made of gold. A sealing member 81 made ofepoxy resin or polyimide resin, etc., covers the first and secondexternal semiconductor elements 71 and 77, the first and second bondingwires 76 and 80, and the lower surface center portion of the bottominsulation film 38.

At least one part of the second upper distributing wiring layer 24 thatincludes the second upper base metal layer 23 is connected to at leastone part of the second lower distributing wiring layer 37 that includesthe second lower base metal layer 36 via vertical conductors 43. Thevertical conductors 43 comprise a base metal layer 43 a made of copper,etc., and a copper layer 43 b, provided on the inner wall surface of apenetrating hole 42. The penetrating hole 42 is provided inpredetermined places of, the base plate 1 that comprises the secondupper insulation film 27, the first upper base metal layer 19, the firstupper distributing wiring layer, the first upper insulation film 17, theinsulation layer 16, and the upper distributing wiring layer or thelower distributing wiring layer 3, the first lower insulation film 31,the first lower base metal layer 32, the first lower distributing wiringlayer 33, and the second lower insulation film 34.

In this case, conductive material 44 made of copper paste, silver paste,or conductive resin, etc., is filled in the vertical conductors 43 forbetter electric conduction of the upper and lower wiring. However,insulative resin may be filled, or the vertical conductors 43 may behollow.

Here, as one example, the columnar electrode 14 for ground of thesemiconductor element 4 is connected to the upper layer wiring 2 servedas the ground wiring via the first upper distributing wiring layer 20and the vertical conductors 43. The columnar electrode 14 for powersource of the semiconductor element 4 is connected to the lower layerwiring 3 served as the power source wiring via the first upperdistributing wiring layer 20 and the vertical conductors 43.

The connecting pads 74, 79 for ground of the first and second externalsemiconductor elements 71, 77, are connected to the upper distributingwiring layer 2 served as the ground wiring via the second lowerdistributing wiring layer 37 and the vertical conductors 43. Theconnecting pads 74, 79 for power source of the first and second externalsemiconductor elements 71, 77 are connected to the lower distributingwiring layer 3 served as the power source wiring via the second lowerlayer wiring 37 and the vertical conductors 43.

The columnar electrode 14 for signal of the semiconductor element 4 andthe connecting pads 74, 79 for signal of the external semiconductorelements 71, 77 are connected via the first upper distributing wiringlayer, the vertical conductors 43, the first lower distributing wiringlayer 33 and the second lower distributing wiring layer 37. Then, theground wiring is connected to the solder ball 27 for ground, the powersource wiring is connected to the solder ball 27 for power source, andthe signal wiring is connected to the solder 27 for signal.

The reason that the size of the base plate 1 is larger than the size ofthe semiconductor element 4 to a certain extent, is for making thearrangement region of the solder ball 27 larger than the size of thesemiconductor element 4 to a certain extent, in accordance with theincrease in number of the connecting pad 7 on the silicon substrate 6,thereby making the size and pitch of the connecting pad (interior partof the of the opening 26 of the top insulation film 25) of the secondupper distributing wiring layer 24, larger than the size and pitch ofthe columnar electrode 14.

By this, the connecting pad of the second upper distributing wiringlayer 24 arranged in a matrix is arranged at not only the regioncorresponding to the semiconductor element 4, but also to the regionthat corresponds to the insulation layer 16 provided outside of theperimeter side surface of the semiconductor element 4. Namely, of thesolder balls 27 arranged in a matrix, at the least, the solder balls 27at the most outer circumference are arranged at a periphery of aposition that is outside the semiconductor element 4.

With this semiconductor device, because the first and second lowerdistributing wiring layers 33, 37 are provided below the base plate 1,and at least one part of the first and second upper distributing wiringlayers 20, 24 and at least one part of the first and second lowerdistributing wiring layers 33, 37 are connected via the verticalconductors 43, the first and second external semiconductor elements 71,77 can be mounted stacked, at the lower surface of the bottom insulationfilm 38. Furthermore, according to this semiconductor device, thoughthree semiconductor elements 4, 71, and 77 are substantially stacked asa whole, because only the first and second external semiconductorelements 71 and 77 are carried out wire bonding, in a structure ofstacking three semiconductor elements and carrying out wire bonding toevery semiconductor element, wire bonding to the external semiconductorelement at the top, can be omitted, the increase of area of the baseplate 1 can be suppressed, and the value of resistance can be reduced.

Next, an example of a manufacturing of this semiconductor device will bedescribed. The situation shown in FIG. 18, is a situation after goingthrough the method shown in FIGS. 2 to 17, described in the firstembodiment.

As shown in FIG. 21, by a screen printing etc., conductive material 44made of copper paste, silver paste, or conductive resin, etc., is filledin the vertical conductors 43. Next, in accordance with need, extraconductive material 44 protruding from the vertical conductors 43 isremoved by a buffing, etc. Next, by the screen printing or the spincoating etc., at the upper surface of the second upper insulation film21 that includes the second upper distributing wiring layer 24, a topinsulation film 25 made of solder resist, etc., is formed.

Also, by the screen printing or the spin coating etc., at the lowersurface of the second lower insulation film 34 that includes the secondlower distributing wiring layer 37, a bottom insulation film 38 made ofsolder resist, etc., is formed. In this case, at the bottom insulationfilm 38 of the part corresponding to the connecting pad of the secondlower distributing wiring layer 37, an opening 39 is formed. At thispoint, an opening 26 is not formed in the part of the top insulationfilm 25 corresponding to the connecting pad of the second upperdistributing wiring layer 24.

Here, the second upper distributing wiring layer 24 that includes thesecond upper base metal layer 23 is completely separated. On the otherhand, the second lower distributing wiring layer 37 that includes thesecond lower base metal layer 36 is not completely separated, and isconnected to a plating current path (not shown) formed at a laterdescribed cutting line (corresponding to dicing line) region.

As shown in FIG. 22, first and second surface layers 70 a and 70 b areformed by electrolytic plating of gold using the bottom insulation film38 as the mask on the lower surface of the second lower distributingwiring layer 37 in the opening 39.

Next, as shown in FIG. 23, an opening 26 is formed in the part of thetop insulation film corresponding to the connecting pad of the secondupper distributing wiring layer 24. Then, as shown in FIG. 24, theadhesive layer 72 of the first external semiconductor element 71 isattached to the lower surface center portion of the bottom insulationfilm 38, and then, the adhesive layer 78 of the second externalsemiconductor element 77 is connected to the lower surface centerportion of the first external semiconductor element 71. Then, theconnecting pads 74 of the first external semiconductor element 71 areconnected to the first surface layer 70 a via the first bonding wires 76made of gold. Thereafter, the connecting pads 79 of the second externalsemiconductor element 77 are connected to the second surface layer 70 bvia the second bonding wires 80.

Or, it may be so that the adhesive layer 72 of the first externalsemiconductor element 71 is attached to the lower surface center portionof the bottom insulation film 38, and then, the connecting pad 74 of thefirst external semiconductor element 71 and the first surface layer 70 aare connected via the first bonding wire 76. Thereafter, the adhesivelayer 78 of the second external semiconductor element 77 is connected tothe lower surface center portion of the first external semiconductorelement 71, and then, connecting pad 79 of the second externalsemiconductor element 77 and the second surface layer 70 b are connectedvia the second bonding wire 80.

By potting, or screen printing, etc., a sealing member 81 made of epoxyresin or polyimide resin, etc., is formed at the lower surface of thefirst and second external semiconductor elements 71, 77, and the bottominsulation film 38 that includes the first and second bonding wires 76and 80. Then, a solder ball 27 is formed by connecting it to theconnecting pad of the second upper re-wring, in the opening 26 and theupper side thereof. Next, a plurality of semiconductor devices shown inFIG. 20 are obtained by cutting the top insulation film 25, the secondupper insulation film 21, the first upper insulation film 17, theinsulation layer 16, the base plate 1, the first lower insulation film31 the second lower insulation film 34 and the bottom insulation film 38between the respectively adjacent semiconductor elements 4.

In this case, when cutting is carried out as the above cutting line,because the second lower distributing wiring layer 37 that includes thesecond lower base metal layer 36 is separated from the plating currentpath that is formed at the cutting line region, the second lowerdistributing wiring layer 37 that includes the second lower base metallayer 36 is completely separated. Here, the surface layers 70 a, 70 bare formed by electrolytic plating, and not by electroless plating. Thisis because, in a case where the surface layers 70 a, 70 b are formed byelectroless plating, the thickness thereof is relatively thin, as to ina case where the surface layers 70 a, 70 b are formed by electrolyticplating, the thickness thereof becomes relatively thick. If thethickness of the surface layers 70 a, 70 b is relatively thin, it ismore likely for a defect of connection by wire bonding to occur. On theother hand, if the thickness of the surface of the layers 70 a, 70 b isrelatively thick, it is most likely for a defect of connection by wirebonding, not to occur.

Third Embodiment

FIG. 25 is a cross-sectional view of a semiconductor device as a thirdembodiment of the invention. The point that the semiconductor deviceshown in FIG. 25 mainly differs from the semiconductor device shown inFIG. 20, is that the first and second external semiconductor elements71, 77 are provided stacked on the top insulation film 25, and thesolder ball 27 is arranged below the bottom insulation film 38. In thiscase, the first and second external semiconductor elements 71, 77, andthe seal member 81 that covers the second bonding wires 76, 80, areformed by a transfer mold method, etc., and when each semiconductorelement is obtained by cutting, the sealing member 81 is also cut.

Fourth Embodiment

FIG. 26 is a plane view showing the substantial parts (for example, asemiconductor device in a state where the sealing member 81, the firstand second bonding wires 76, 80, etc. are omitted), of a semiconductordevice, as a fourth embodiment of the invention. Because a topinsulation film 25, etc., exists between the semiconductor element 4 andthe first external semiconductor element 71, in this semiconductordevice, a semiconductor element with a large exterior size is used toprovide first and second surface layers 70 a, 70 b which are connectedvia the connecting pads of the first and second external semiconductorelements 71, 77 (not shown), and the first and second bonding wires (notshown), on the top insulation film 25 that corresponds to the region inthe semiconductor element 4.

In a case where the first and second external semiconductor elements 71,77 are directly stacked on the semiconductor element 4 provided on thebase plate 1, a connecting pad that is connected via three semiconductorelements 4, 71, and 77, and the bonding wire, is provided at the outside of the mounting region of the semiconductor element 4, on the baseplate 1, therefore, the size of the base plate 1 becomes quite large. Onthe other hand, with the semiconductor device shown in FIG. 26, asdescribed above, because the first and second surface layers 70 a, 70 bthat are connected via the connecting pads of the first and secondexternal semiconductor elements 71, 77, and the first and second bondingwires, are provided on the top insulation film 25 that corresponds tothe region in the semiconductor element 4, the size of the base plate 1can be made quite small.

Fifth Embodiment

FIG. 27 is a front view of a semiconductor device as a fifth embodimentof the invention. Within this semiconductor device, a plurality ofsemiconductor blocks, for example four semiconductor blocks, thatcorrespond to the semiconductor device shown in FIG. 20, are stacked. Inthis case, a semiconductor block 91 of the bottom layer is basically thesame as the semiconductor device shown in FIG. 20. However, the size ofthe semiconductor block 91 is a little larger than the semiconductordevice shown in FIG. 20, and at the periphery of the sealing member 81,an upper connecting pad 92 is provided, on the upper surface of thesemiconductor block 91. Another semiconductor block 93 is basically thesame as the semiconductor block 91 at the bottom layer. However, thesemiconductor block 93 does not comprise a solder ball 27. Instead, asolder ball 95 is provided below a lower connecting pad 94 that isprovided at the region corresponding to the periphery of the sealingmember 81, at the lower surface of the semiconductor block 93. At theupper surface of the semiconductor block 93, an upper connecting pad 96is provided at the periphery of the sealing member 81.

Here, the upper connecting pads 92, 96 are formed by a part of theconnecting pad of the second lower distributing wiring layer 37, shownin FIG. 20. In this case, a surface layer may be formed in the opening39 of the bottom insulation film 38 for exposing the connecting pad ofthe second lower distributing wiring layer 37. The lower connecting unit94 is formed of the connecting pad of the second upper distributingwiring layer 24 shown in FIG. 2. In this case, the connecting pad of thesecond upper distributing wiring layer for forming the lower connecting94 is provided only at the region corresponding to the periphery of thesealing member 81.

The semiconductor block 93 of the second layer is mounted on the bottomlayer semiconductor block 91, by the solder ball 95 of the semiconductorblock 93 being attached to the upper connecting pad 92 of the bottomlayer semiconductor block 91. The semiconductor blocks 93 of the thirdlayer and fourth layer are mounted on the semiconductor block 93 of thesecond layer and the third layer, by the solder balls 95 of the thirdlayer and fourth layer being attached to the upper connecting pad 96 ofthe semiconductor block 93 of the second layer and the third layer. In acase where the thickness of the sealing member 81 is 0.5 to 0.6 mm, asolder ball 95 with a diameter of 0.8 to 1.0 mm is used.

In each embodiment of above, a case where two external semiconductorelements are stacked and mounted is described. However, it is notlimited to this, and a case where one external semiconductor element ismounted, or three or more external semiconductor elements are stackedand mounted, is possible. In the above embodiment, a case where both theupper distributing wiring layer and the lower distributing wiring layerhave two layers is described. It is not limited to this, and the upperdistributing wiring layer and lower distributing wiring layer may haveone layer or three or more layers, and also, the number of layers do nothave to be equal, and may be a different number of layers. However, in acase where the number of layers is the same, bowing of the semiconductorcan be reduced.

In the above embodiment, respectively adjacent semiconductor elements 4are cut. However, it is not limited to this, and two or moresemiconductor elements 4 may be cut, as one pair. In this case, aplurality of external semiconductor elements may be stacked to eachsemiconductor element 4. The semiconductor element that is one pair by aplurality of semiconductor elements 4 may be the same type, or adifferent type.

In the above embodiment, the semiconductor element 4 comprises acolumnar electrode 14 as an electrode for external connection. However,it is not limited to this, and the semiconductor element 4 may comprisea distributing wiring layer 13 that includes a connecting pad as theelectrode for external connection, instead of comprising the columnarelectrode. Or, the semiconductor element 4 may be a semiconductorelement that comprises a connecting pad 7 as the electrode for externalconnection (namely, a bare chip), instead of comprising a columnarelectrode or a distributing wiring layer.

In the present invention, a first semiconductor element that comprises aplurality of electrodes for external connection is in a sealed state, bymounting the first semiconductor element on a base plate, and coveringthe periphery thereof by an insulation material, and the upper surfacethereof by an upper insulation film. A second semiconductor element isconnected to at least either an upper distributing wiring layer, whichis provided on the upper insulation film, or a lower distributing wiringlayer, which is provided directly on the base plate, or via the lowerinsulation film. By adopting this kind of structure, the presentinvention can provide a semiconductor device and a manufacturing methodof the semiconductor device, wherein further thinning can be carried outwhile maintaining a small mounting surface, and securing reliability ofthe strength of the connecting unit.

Various embodiments and changes may be made thereunto without departingfrom the broad spirit and scope of the invention. The above-describedembodiments are intended to illustrate the present invention, not tolimit the scope of the present invention. The scope of the presentinvention is shown by the attached claims rather than the embodiments.Various modifications made within the meaning of an equivalent of theclaims of the invention and within the claims are to be regarded to bein the scope of the present invention.

This application is based on Japanese Patent Applications No.2003-379547 filed on Nov. 10, 2003 and No. 2003-395313 filed on Nov. 26,2003 and including specification, claims, drawings and summary. Thedisclosure of the above Japanese Patent applications is incorporatedherein by reference in their entirety.

1. A semiconductor device comprising: a first semiconductor element thathas a plurality of electrodes for external connection; an insulationmember provided at the periphery of the fist semiconductor element; anupper wiring structure formed on an upper surface of the firstsemiconductor element and the insulation member; a lower wiringstructure formed on a lower surface of the first semiconductor elementand the insulation member; and a second semiconductor element that ismounted on at least one of the upper wiring structure and the lowerwiring structure.
 2. The semiconductor device according to claim 1,further comprising a conductor that penetrates the insulation member toelectrically connect the upper wiring structure and the lower wiringstructure.
 3. The semiconductor device according to claim 1, wherein thesecond semiconductor element is mounted only on one of the upper wiringstructure and the lower wiring structure, and solder balls are mountedon the other.
 4. The semiconductor device according to claim 1, whereinthe upper wiring structure comprises upper insulation films having amultiple-layer structure, and upper wiring layers having amultiple-layer structure.
 5. The semiconductor device according to claim4, wherein a top layer of the upper wiring layers includes a connectingpad, and the upper layer wiring structure includes a top insulation filmthat covers the top layer of the upper wiring layer excluding theconnecting pad.
 6. The semiconductor device according to claim 5,further comprising a solder ball provided on the connecting pad of theupper wiring of the top layer.
 7. The semiconductor device according toclaim 5, further comprising a surface layer provided on the upper wiringof the top layer.
 8. The semiconductor device according to claim 7,further comprising a second semiconductor element mounted on theinsulation film of the top layer.
 9. The semiconductor device accordingto claim 7, wherein the second semiconductor element comprises bondingwires connected to the surface layers.
 10. The semiconductor deviceaccording to claim 1, wherein the lower wiring structure includes thebase plate, the lower insulation film, and the lower wiring layer. 11.The semiconductor device according to claim 10, wherein the base platecomprises at least one of the upper wiring provided on the upper surfaceof the base plate and the lower layer wiring provided on the lowersurface of the base plate.
 12. The semiconductor device according toclaim 11, wherein at least one of the upper wiring and the lower wiringis a ground wiring.
 13. The semiconductor device according to claim 10,wherein the base plate is made of thermosetting resin including areinforcer.
 14. The semiconductor device according to claim 1, whereinthe lower wiring structure includes lower insulation films having amultiple-layer structure, and lower wiring layers having amultiple-layer structure.
 15. The semiconductor device according toclaim 14, wherein a bottom layer of the lower wiring layers include aconnecting pad, and the lower wiring structure includes a bottominsulation film that covers the bottom layer of the lower distributingwiring, excluding the connecting pad.
 16. The semiconductor deviceaccording to claim 15, further comprising a solder ball intervenedbetween the second semiconductor device and the bottom layer of thelower wiring layers.
 17. The semiconductor device according to claim 15,further comprising surface layers provided on the bottom layer of thelower wiring layer.
 18. The semiconductor device according to claim 17,further comprising a second semiconductor device mounted on the bottominsulation film.
 19. The semiconductor device according to claim 18,wherein the second semiconductor devices comprise bonding wires that areconnected to the surface layers.
 20. The semiconductor device accordingto claim 1, wherein the electrodes for external connection of the firstsemiconductor element is a columnar electrode with a height equal to orhigher than 60 μm.
 21. The semiconductor device according to claim 1,wherein the first semiconductor element includes an overcoat film, andthe electrodes for external connection are provided on the overcoat. 22.The semiconductor device according to claim 21, wherein the firstsemiconductor element comprises an insulation film provided on theovercoat between the electrodes for external connection.
 23. Amanufacturing method of the semiconductor device, comprising: forming afirst semiconductor element wherein each semiconductor element comprisesa plurality of electrodes for external connection, by the base plate,the insulation film, and the upper insulation film, by respectivelysealing; forming an upper wiring layer on the upper insulation film;forming a lower wiring layer below the base plate; mounting a secondsemiconductor element on at least either the upper wiring layer or thelower wiring layer; and obtaining a plurality of semiconductor devicesthat comprise at least one semiconductor element and at least one secondsemiconductor element, by cutting the base plate, the insulation member,and the upper insulation film.
 24. The manufacturing method of thesemiconductor device, according to claim 23, wherein forming the firstsemiconductor element by respectively sealing, comprises: preparing abase plate having a size that can arrange a plurality of firstsemiconductor elements; fixing the first semiconductor elements so thata distance is provided therebetween, on the base plate; forming theinsulation member on the base plate at the periphery of the each firstsemiconductor element; and forming the upper insulation film on thefirst semiconductor element.
 25. The manufacturing method of thesemiconductor device, according to claim 24, wherein forming the firstsemiconductor element by respectively sealing, comprises: hot pressingthe upper insulation film, the first semiconductor element, theinsulation member, and the base plate, by using hot pressing plates. 26.The manufacturing method of the semiconductor device, according to claim25, wherein the base plate comprises the upper wiring layer and thelower wiring layer.
 27. The manufacturing method of the semiconductordevice, according to claim 26, comprising: further forming a penetratinghole to the base plate, the insulation member, and the upper insulationfilm, and forming conductors that connects the upper wiring layer atleast one of the upper wiring or the lower wiring, in the penetratinghole.
 28. The manufacturing method of the semiconductor device,according to claim 23, further forming a penetrating hole to the baseplate, the insulation member, and the upper insulation film, and formingconductors that connect the upper wiring layer and the lower wiringlayer, in the penetrating hole.
 29. The manufacturing method of thesemiconductor device, according to claim 26, wherein at least one of theupper wiring and the lower wiring is connected to the conductors. 30.The manufacturing method of the semiconductor device, according to claim23, wherein the electrode for external connection is a columnarelectrode that has a height equal to or higher than 60 μm.
 31. Themanufacturing method of the semiconductor device, according to claim 23,wherein the first semiconductor element includes an overcoat, and theelectrode for external connection is provided on the overcoat.
 32. Themanufacturing method of the semiconductor device, according to claim 31,wherein the first semiconductor element comprises an insulation filmprovided on the overcoat between the electrodes for external connection.